Telemicroscopy and Remote Microscopy at Cambridge University Engineering Department

In 1995, our group began a project to interface the Scanning Electron Microscope (SEM) to the World Wide Web (WWW), using a LEO 440 instrument as a practical basis for the research.

The objectives were threefold:

Web technologies possess a number of key advantages for network applications.

Web servers and browsers (such as Netscape Navigator and Internet Explorer) are designed to transfer data in a variety of formats across the Internet and corporate and academic Intranets in a transparent fashion to the user. This freed us from the need to "reinvent the wheel" in developing our own protocols for achieving data and image transfer across diverse types of network.

Despite occasional commercial skirmishes, standards bodies have managed to ensure that by and large the principal software tools of the Web are platform-independent. In particular, whilst a given SEM may be committed to a single operating system, images relayed via the Web can be downloaded onto graphical browsers executing on PCs, Apple Macs or UNIX workstations, eliminating the need for specific hardware and operating system environments at the remote sites.

In addition, all of the necessary software was and is freeware - enabling us to conduct this research on the traditional shoestring budget of academia!

The remote control software, which we proceeded to implement, consists of three components, namely a set of Web pages forming the user interface, a Web server to transfer these pages to the remote user, and a translation program to convert requests from the remote user into instructions understood by the SEM. The remote user only needs a Web browser and network access to connect to the instrument. The intervening network communication is handled by the hypertext protocols of the web software.

The package allowed the remote user to obtain and set the values of virtually every instrument parameter on the instrument, run macros (sequences of SEM instructions), execute other applications, and to acquire static images of up to 1024 by 768 pixels from the SEM. All of these functions were provided in terms of icons and forms on the Web pages.

For dynamic imaging, we used CU-SeeMe™, a desktop video-conferencing package originally developed by Cornell University. We modified CU-SeeMe such that SEM images were pumped directly into a CU-SeeMe client running on the SEM. (The SEM image stream replaced the normal input from a video camera). The video stream was then passed via CU-SeeMe protocols to a CU-SeeMe client running on the computer of the remote user. This provided our second application, namely remote collaboration.

We presented this stage of the research at the Scanning '96 conference (see [1]) and were invited to contribute a full-length paper on the work for Scanning: The Journal of Scanning Microscopies(see [5])).

In 1996, the Java programming language (from Sun Microsystems) was coming into prominence as the most effective means for distributing executable programs over the Web.

We designed a number of Java applets to provide "proof of concept" for a further applications, namely remote instrument monitoring . One of the earliest and still a very useful applet automatically requested vacuum and filament current readings from the SEM, displaying the resulting data in both textual and graphical forms. This allowed a remote user to runup a filament and stabilize the gun from a remote location. In our case we are using a lanthanum hexaboride filament and this takes some ten to twenty minutes to stabilize.

Our initial Java experiments were reported at the EUREM'96 conference (see [2]).

Another project within the group has been the application of artificial intelligence techniques, in particular knowledge-based methods, to the domain of scanning electron microscopy. One facet of that research has been the design and implementation of an expert system (FIRST A.I.D.) for assisting service engineers with the task of instrument fault diagnosis. It was realised quickly that if expertise was combined with reliable information and images direct from the affected instrument, the likelihood of achieving an accurate diagnosis was much higher. Hence we interfaced FIRST A.I.D. to the Internet via our existing Web-based control software, and allowed the expert system to directly interrogate the instrument over the network. On the basis of the expertise in the knowledge base and information obtained from the distant SEM, FIRST A.I.D. can correct certain faults remotely.

More details on this remote diagnosis application can be found here.

We presented the results of the FIRST A.I.D. system to the artificial intelligence community at the Expert Systems '96 conference in December 1996 (see [3]) and reported on continuing progress at the Scanning '97 conference in April 1997 (see [4]). A further paper discussing the broader issues concerning our "information client" approach and its architectural implications for expert systems in general has been accepted by IEEE Intelligent Systems and is currently in press (see [7]).

One of our erstwhile colleagues (Dr. Gopal Chand) has since become a R&D Software Engineer with LEO Electron Microscopy Ltd., and as part of the technology transfer process, has reimplemented our remote control software as the industrial-strength NetSEM package which can be freely downloaded from here .

We continue to collaborate closely with LEO on a number of telemicroscopy and remote microscopy applications. An article on our recent work was published in Microscopy & Analysis (see [6]).


1. "World Wide Web Controlled SEM"

G Chand, BC Breton, NHM Caldwell & DM Holburn

Paper presented at the Scanning '96 conference. Extended abstract in Scanning: The Journal of Scanning Microscopies, (April 1996),Vol 18, 3, pp201-202.

2. "A Java Powered SEM"

BC Breton, G Chand, NHM Caldwell & DM Holburn

Paper presented at the 11th European Congress on Microscopy (EUREM '96). (Proceedings in press)

3. "An Expert System for Fault Diagnosis in the Scanning Electron Microscope"

NHM Caldwell, BC Breton & DM Holburn

Paper presented at the Expert Systems '96 conference. Full paper in Applications and Innovations in Expert Systems IV, pp 177-188, Cambridge University Press, 1996.

4. "FIRST A.I.D. : Using Remote Microscopy and Artificial Intelligence for SEM Fault Diagnosis"

NHM Caldwell, BC Breton & DM Holburn

Paper presented at the Scanning '97 conference. Extended abstract in Scanning: The Journal of Scanning Microscopies, (April 1997),Vol 19, 3, pp204.

5. "World Wide Web Controlled Scanning Electron Microscope"

G Chand, BC Breton, NHM Caldwell & DM Holburn

Full length version of (1), published in Scanning: The Journal of Scanning Microscopies, (June 1997), Vol 19, 4, pp292-296.

6. "Remote Microscopy in the Real World"

BC Breton, G Chand, NHM Caldwell & DM Holburn

Microscopy & Analysis, (September 1997), pp19-21.

7. "Remote Instrument Diagnosis on the Internet"

NHM Caldwell, BC Breton & DM Holburn (1998)

Paper published in IEEE Intelligent Systems Vol 13, 3, pp70-76.

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